Multiple pushbutton switch with sliders operating switch arms

ABSTRACT

983,571. Cam-operated switches. GENERAL ELECTRIC CO. July 12, 1961 [July 14, 1960], No. 25224/61. Heading H2B. A multiple push-button switch similar to that of Specification 605,170 and having normally-closed contacts 70, 100 which may be opened by cam surfaces on sliders A... E which are movable, longitudinally by pushbuttons 62, also has one or more sets of normally open contacts 70, 111 which are similarly operable. Each button 62 actuates two pushrods, such as 42, having rounded ends 56 acting on sloping surfaces on the sliders.; A slider F has hook portions which retain any button in the depressed position against the bias of a return spring 66 until released by depression of a further button. A further slider G causes momentary actuation of one set of contacts during each depression of a button.

March 31,1964 P. HUTT 3,127,482

MULTIPLE PUSHBUTTON SWITCH WITH SLIDERS OPERATING SWITCH ARMS March 31,1964 HUT-r 3,127,482

MULTIPLE PUSHBUTTON SWITCH WITH SLIDERS OPERATING SWITCH ARMS Filed July14, 1960 '7 Sheets-Sheet 2 P. HUTT March 31, 1964 MULTIPLE PUSHBUTTONSWITCH WITH SLIDERS OPERATING SWITCH ARMS 7 Sheets-Sheet 3 Filed July14, 1960 March 3l, 1964 p, HUTT 3,127,482

MULTIPLE PUSHBUTTON SWITCH WITH SLIDERS OPERATING SWITCH ARMS Filed July14, 1960 '7 Sheets-Sheet 4 3641 sel asm am, 360

se; sa, asd

March 31, 1964 P. HUTT 3,127,482

MULTIPLE PUSHBUTTQN swITcH WITH sLIDERs OPERATING SWITCH ARMS Filed Jly14, 1960 7 Slfleens-Sheeil 5 March 31, 1964 P, HUTT 3,127,482

MULTIPLE PUSHBUTTON SWITCH WITH SLIDERS OPERATING SWITCH ARMS Filed July14, 1960 7 Sheets-Sheet 6 March 31, 1964 P. HUTT 3,127,482

MULTIPLE PUSHBUTTON SWITCH WITH SLIDERS OPERATING SWITCH ARMS Filed July14, 1960 7 Sheets-Sheet 7 F/9. az

57a. 5w Je .a g s70- rf rrrrrmruuumr United States Patent @moe 3,127,482Patented Mar. 31, 1964 3,127,482 MULTIPLE PUSHBUTTGN SWITCH WITH SLIDERSOPERATING SWITCH ARMS Philip Hutt, Milford, Conn., assignor to GeneralElectric Company, a corporation of New York Fried Jury 14, 1ers, ser.No. 42,375 lll Claims. (Cl. 200-5) This invention relates to apushbutton switch, and particularly, a multiple pushbutton switch with aseries of manually controlled reciprocating sliders for controlling theoperation of several circuits connected through the switch.

Multiple pushbutton switches of the type exemplified by the AndrewsPatent No. 2,431,904 (which is assigned to the same assignee as is thepresent invention) have been used in great numbers as appliance switchesfor electric ranges, washing machines, and room air conditioners, etc.,to control the circuitry thereof. In such switches, a speciallyconstructed group of longitudinally extending sliders are positioned inside-by-side relationship within a switch base. These sliders arearranged to transmit actuating force from manually depressible pushrodsto movable Contact blades and also provide an interlocking mechanism forthe switch by preventing simultaneous operation of any other pushrodswhen one pushrod is being depressed and returning any previouslydepressed pushrod back to its outer (normal) position upon thesubsequent depression of another of the pushrods. To effect thesefunctions, the sliders are formed with groups of diagonal workingsurfaces that are dis` posed in general alignment to cooperate with thepushrods, and cam surfaces for actuating the movable contact blades. Anactuating portion of an associated pushrod is extended through eachaligned group of working surfaces and the working surfaces are soarranged on the respective sliders that predetermined movement ofcertain sliders will occur when any one of the pushrods is depressed andany previously depressed pushrod will be returned to its outer (normal)position. The cam surfaces are formed on one of the edges of certain ofthe sliders and positioned with respect to associated movable contactblades in the switch housing so that longitudinal movement of a sliderupon which a carn surface is formed in a particular direction to theright or left within the switch will cause a normally closed movablecontact blade to be cammed open.

In many multiple pushbutton switch applications, it is desirable thatthe switch be capable of controlling a large number of circuits. Toeiiiciently effect this purpose, by means of prior art practice thenumber of sliders required to control these circuits has necessitated anundesirable increase in cost of the over-al1 switch as well as anincrease in the switch dimensions and an increased amount of frictionaldrag between the respective sliders. It is therefore desirable toprovide an improved multiple pushbutton switch of the aforementionedtype which is capable of controlling a large number of circuits whilerequiring a substantially reduced number of sliders.

The principal object of the present invention is to provide an improvedmultiple pushbutton switch with a novel and low-cost means forcontrolling a relatively large number of circuits.

A further object of this invention is to provide an improved multiplepushbutton switch which is capable of controlling a relatively largenumber of movable contacts with a substantially reduced number ofreciprocating sliders.

A still further object of my invention, is to provide an improvedmultiple pushbutton switch having certain movable contact blades `whichare cammed open and cery ing sliders.

tain movable contact blades which are cammed closed by reciprocatingsliders.

In carrying out my invention, in one form thereof, I apply it to amultiple pushbutton switch unit for controlling a plurality of circuitsby movement of reciprocat- Each slider has a series of inclined workingsurfaces which are acted upon by certain pushrods. Certain sliders alsohave cam surfaces for engaging a plurality of switch arms or movablecontact blades. The switch arms are all biased in one direction to anormal position and are movable by the cam surfaces of certain of thesliders against their biasing forces to a second position. By myinvention, a first type of fixed contacts is provided which isengageable by selected ones of the switch arms when the arms are intheir normal position. This first type of fixed contacts along with itsassociated switch arms thus provides a plurality of normally closedpairs oi contacts in the switch which are cammed open. A second type ofxed contact is positioned so as to be engageable by at least one otherof the switch arms when the other arm is in its second position. Thissecond type of xed contact along with its associated switch arm providesat least one normally open pair of contacts in the switch unit which iscammed closed. By using normally closed switch arms which are cammed toan open position as well as normally open switch arms which are cammedto a closed position in my multiple pushbutton switch unit, asubstantial increase in circuit controlling flexibility is thus providedwithout necessitating any increase in the number of sliders required tocontrol a large number of circuits. An improved multiple pushbuttonswitching unit which is low in cost and novel in structure has thus beenobtained.

Further aspects of my invention will become apparent hereinafter, andthe specification concludes with claims particularly pointing out anddistinctly claiming the subject matter which I regard as my invention.The invention, however, as to organization and method of operation,together with other objects and advantages thereof, may best beunderstood by reference to the following description when taken inconjunction with the accompanying drawings in which:

FIG. l is a top View, partially in section and partially broken away, ofan improved multiple pushbutton switch unit embodying my invention inone form thereof;

FIG. 2 is a side View of the switching unit of FIG. l with onepushbutton shown in section and one pushbutton in its extreme depressedposition;

FIG. 3 is a sectional View taken generally along the line 3--3 of FIG.2, showing one of the movable arms of my switch unit which is cammed toa contacts open position;

FIG. 4 is a cross-sectional view taken generally along the line 4-4 ofFIG. 2, showing one of the movable arms of the switch unit which iscammed to a closed position;

FIG. 5 is an end view of the switch of FIG. l;

FIG. 6 is a penspective view of the switch unit of FIG. l with themounting bracket, `light barrier and pushbuttons exploded therefrom;

FIG. 7 is a fragmentary exploded perspective view of a portion of theswitch unit of FIG. l showing the movable switch arms and their twotypes of mating fixed contacts;

FIG. 8 is a bottom View of the switch unit of FIG. 1 with most of thecover plate and one vof the switch arms partially broken away to showdetails of the switching structure;

FIG. 9 is a cross-sectional view taken generally along the line 9-9 ofFIG. 8;

FIG. 10 is an exploded perspective view of a iixed 3 contact and itsassociated terminal for one of the contact pairs of my switch unit whichis cammed closed by the sliders;

FIG. 1l is a perspective view of `a pair of switch arms which are axedto 'a series connected integral double terminal;

FIG. y12 is a perspective View of one of the tixed contacts yof myswitch unit and its associated terminal, for one of the contact pairs ofmy switch imit which is cammed open; i FIG. 13 is a layout of thevarious sliders of my multiple pushbutton switching unit;

FIGS. 14-17 inclusive, are diagrammatic views of the momentary anddetent sliders illustrating the effect they have upon the pushrods ofexemplary pushbuttons during the successive depression thereof;

FIGS. 18 and 19 rare diagrammatic views illustrating the camming open`of one of the switch arms by its associated actuating slider;

FIGS. 20-22 inclusive, are diagrammatic views illustrating the cammingclosed of certain movable contact blades by their yassociatedpredetermined slider combinations; and

FIG. 23 isa diagrammatic view of the contact arrangement in my improvedmultiple pushbutton switch unit.

Referring in detail Vto the drawings, and in particular to FIGS. 1 and2, there is shown a multiple pushbutton switch unit 2 wherein myinvention has been advantageously employed. Certain features of thisswitch, other than those claimed herein, are the invention of Stewart A.Woodward, and are described in detail and claimed in the copendingapplication of said Woodward, Seria-l Number 42,815 led concurrentlyherewith and assigned to the same assignee as the present invention. Theswitch housing 4 comprises left and right hollow bases 6 and 8respectively (as shown in FIG. 2), which are held together by mountingbracket 10` `and ia relatively thin elongated cover plate 12. Bases 6and are similar in construction, having oppositely disposed closed outerend walls 14 and 16 respectively, communicating lopen inner ends 18 andZtl respectively, and open bottoms. As best seen by viewing FIGS. 2, 5,and 6, bracket 10` is channel shaped, and straddles central uprightportions 22 and 214 of the two bases 6 and S to fasten them together inan end-to-end relationship by means of screws 26. rIlhe screws 26 areextended through apertures 28 in horizontal section 30 of bracket 1t) toengage threaded recesses 32 of the upright portions 22 and 24, for rmlysecuring the bases 6 and 8 together. (See FIG. 6.) With bracket V10lattached to the two bases, the two longitudinally extending sides 311of the bracket engage the oppositely disposed longitudinally extendingsides 22a, 22b, 24a, and Zdb of the upright portions 22 and 24 topreclude Iany lateral movement of the bases and rigidly secure them tothe bracket. (-See FIGS. 3 and 4.) As may be clearly seen in FIGS. l and2, when the bases 6 and 8 are secured together by bracket 1t), they arespaced apart slightly so that a narrow gap 34 exists between theadjacent lovver portions 33 and 35 lof the bases at their open innerends 18` and 20. This gap 34 `also extends upwardly on each side ofhousing 4 to the bottom edges of the bracket sides 31 (as seen in FIG.2), being formed by bridging the two bases 6 and 8 while they are spacedslightly apart, as shown in FIG. `6, by the attachment of bracket 10 andcover plate 12 thereto. By for-ming switch housing 4 from the two hollowbases 6 `and 3 joined together in slightly spaced apart relationship bybracketiltl, it has been found much easier to control the tolerances(i.e., the dimensional relationships) of the switch housing and reducesthe possibility of the occurrence of molding problems in manufacturingbases for such la switch. The particular construction of bases' and 8along with the means for mounting them together in a multiple pushbuttonswitch comprises the invention of Stewart A.

d Woodward, and this construction and arrangement are described andclaimed in hisraforesaid coperrding application Serial No. 42,815.

To close the open bottom iof hollow bases 6 and 8 of switch 2 andcooperate with these bases to provide a compact housing structure `forthe operating mechanism of the switch, the elongated cover plate 12engages the underside of each base (as shown in FIGS. 2 and 5), beingsecurely attached thereto by spaced oppositely disposed terminals 36 and37 of the fixed and movable contacts, respectively, which shall bedescribed in detail hereinafter. These terminals, as shownrepresentatively by movable contact *terminal 37a in FIGS. 2, 6, and 8each extend through cover plate slots 38 (FIG. 8) and aligned oroverlying slots 39 (FIG. 3) formed in the upper wall of the base lowerportions, being lapped over in the well-known manner to hold theterminals in place and secure the cover plate and bases together. (SeeFIG. 2.)

To actuate the various switches of my multiple pushbutton switch unit 2,spaced pairs of adjacent pushrods or actuators 41-50 are extendeddownwardly (as shown in FIG. 9) through appropriate slots formed inbracket section 39 and through top walls 52 and 54 of the bases 6 and 8,into the hollow base portions 53 and 55. These pushrods are reciprocablymovable in pairs having integral cylindrically congured actuatingportions 56 at their innermost ends which cooperate with pairs ofassociated aligned groups of inclined upper working edges 1 1@ ofsliders A-E to operate the switches. The purpose behind the arrangementof the pushrods in pairs shall become apparent hereinafter. Moreparticularly, sliders A-E are disposed in parallel side-by-siderelationship (as shown in FIG. 8). These sliders reciprocatelongitudinally in response to the selective depression of pairs ofpushrods to control the positioning of switch arms or movable contactblades 6tlg-60h and 50i-60g. 4(See FIG. 8.) The lower edge of each ofthe sliders A-E, as shown in FIG. 13, has one or more cam surfacesformed upon it. These cam surfaces (a-h and jq) have been identiiied inFIG. 13 by the lower case reference letters according to the lettersuiix of the switch arm which the cam surface has been designed tocontrol. As an example, cam surface A-a has been formed on lower edge ofslider A for the purpose of controlling the positioning of switch arm60a. It will be noted that in FIG. 13, the reference letters ascribed tocertain slider cam surfaces have been underlined for emphasis (e.g., g).The purpose of such identification is to distinguish between camsurfaces that cam certain switch arms open (these cam surfaces beingidentified by an ordinary letter) and cam surfaces that cam other switcharms closed (these surfaces being identiiied by an underlined letter).The purpose and effects of using the two diierent types of cammingaction by the sliders in my switch unit shall be described in detailhereinafter. The Various cam surfaces a-h and j-q are thus arranged onthe sliders A-E to alternately engage certain movable contact switcharms and thereby effect the opening and closing of predetermined contactpairs in certain operating positions of these sliders.

In the preferred form of my invention as illustrated,` the inclinedworking edges 1 1() of the sliders A-E are: arranged on each slider inthe form or" consecutive adjacent pairs of similar or coincident edges.In viewing FIG. 13 of the drawings, it will be noted that the inclinedworking edges of the associated pairs of edges of the sliders A-E havethus been given the same reference numeral to indicate that they aresimilar and operated by the same pair of pushrods. The inclined workingedges on the respective sliders are disposed in the switch unit in theform of generally aligned groups to cooperate with pairs of associatedpushrod actuating portions as each pair of pushrods reciprocates. Thearrangement of Athe inclined working edges of the sliders is such thatthe dilerent sliders A-E allow only one pair of pushrods.

l1-50 to be fully depressed at any one time and certain of the slidersact upon any previously depressed pushrod pair to return it to itsoutermost position upon the subsequent depresison of another pair ofpushrods.

Turning now to a consideration of the means for manually controllingeach pair of associated pushrods in my switch unit 2, as shown in FIGS.2 and 7, each pair of the pushrods 411-50 is equipped with a pushbutton62 which is press tit to the bifurcated outer ends 64 of the pushrods.More particularly, the pushbuttons 62 each have three inner cavities orrecesses 62a, 62b, and 62e formed in the underside thereof. (See FIGS. 2and 7.) Cavities 62a and 62h receive the bifurcated outer ends 64 of anassociated pair of pushrods. Cavity 62C is disposed between cavities6211 and 6211 and is generally cylindrical in configuration forreceiving one end 66a of compression spring 66. The other end 66h ofeach spring 66 tits around a base projecting boss 68 or the head of oneof the screws 26 to engage bracket 10. The arrangement of the springends in button cavity 62C and around the bases or screws, is such thatthe spring 66 may run in compresison between bracket and button 62, witha minimal lateral movement. Suitable apertures have been formed in thebracket section 30 so that bosses 68 of the base top walls 52 and 54project outwardly from the bracket intermediate each pair of bracketslots through which the pushrods are extended. (See FIG. 7.) It shouldalso be noted that light barrier 69 of dark material is suitablypositioned between horizontal section 30 of the bracket and the bottomsof the buttons, as shown in FIG. 1.

It will thus be seen that each pushbutton 62 is spring biased to itsoutermost position by compression spring 66 and is also pressed intoengagement with the bifurcated ends of an adjacent pair of parallelpushrods. rl`he pushrods of each pair extend through their appropriateslots in bracket 10 and the top base walls so that the actuatingportions 56 of each pair of pushrods transversely overlie coincidentpairs of diagonal working edges of the sliders A-E. By arranging thepushrods in pairs, it has been found that the action of each pushbutton62 upon depression thereor is conveniently stabilized by thereciprocating motion in unison of the associated pushrods. This improvedpushbutton action also provides more accurate control over the movementof each pair of pushrods and enhances the dependability and durabilityof my multiple pushbutton switch unit 2. The particular construction ofthe pushbutton 62 and its cooperating pair of pushrods along with thecooperating associated switch structure comprises the invention ofStewart A. Woodward, and this construction and arrangement are describedand claimed in his aforesaid application Serial No. 42,815.

Turning now to a consideration of the circuit opening and closingelements of my multiple pushbutton switch unit, in viewing FIG. 8, itwill be noted that movable contact switch arms or blades 60ct-60h, and60j-6tlq are all of the same conguration and dimensions. (Blades 6dr and60s are identical to these, but atypical in their operational aspects,and therefore shall be discussed hereinafter.) These arms are suspendedin cantilever fashion from their associated supporting terminals whichare located on one side of the switch housing, and they are spaced apartin parallel relationship near the bottom of the housing with each bladehaving a movable contact button 70 extruded through an opening formed inthe free end 74 thereof. (See also FIG. 11.) Blades 6i) (as shownrepresentatively by blades 6011 and 690 in FIG. 11) are L-shaped andinclude a raised intermediate portion 76 in the elongated section thatcarries the contact button. Portion 76 has a V-shaped cross-section toenhance the strength of the contact blade and furnish a narrowmechanical contacting surface for engagement with slider cam surfaces.The shorter section 75 of each blade is turned over to furnish a supportfor the blade, having a slot formed therein for that purpose. Eachmovable contact supporting terminal has one or two pairs of adjacentlanced projecting iingers 82 (as illustrated by the integral doublebridging terminal 37110 of FIG. 1l with its attached blades). Thesupporting portion 78 of each movable contact blade is attached to itsassociated supporting terminal by bending over each pair of the ngers82', as shown in FIG. 1l, after they have received slot 80 of themovable contact blade.

To support the movable contact blades and fulll certain circuitrequirements in my switch unit, the movable contact terminals 37 are offour general types. All of these types may be understood by furtherreference to the perspective view of the integral double bridgingterminal 37110 shown in FIG. 11. This terminal, as shown in full,provides a long blade section S3 having a single outer blade portion 84with a detent hole formed therein for engagement with an associatedquick connecting terminal, and a short blade section 86 connected tolong section 83 by bridge 88. Another type of double bridging movablecontact terminal, such as, for example, terminal 3711]' (FIG. 8) isessentially similar to terminal 37110 (FIG. 11) except that long section83 is shortened as suggested by the dot-dash lines thereof in FIG. l1,so that the terminal has no outer blade portion and coi prises twosimilar short sections which are connected together by bridge 88. Athird type of movable contact terminal, such as, for example, terminal37a (FIG. 8) consists of a single long section with the sameconfiguration as section 83 of terminal 37110 (including the outer bladeportion). The fourth type of movable contact terminal, such as, forexample, terminal 37k of FIG. 8 is a single short section similar tosection 86 of FIG. 1l, having no outer blade portion.

Turning now to a very important aspect of my invention, in viewing FIG.8, it will be noted that my switch unit 2 has two types of fixedcontacts therein. Fixed contact terminals such as 36a, 36h, 36g, 36h,36j, and 36q are each of the type shown in FIG. 12. This terminalincludes a long blade section 90 having an outer blade portion 92 with adetent hole formed therein for engagement with an associated quickconnecting terminal. Connecting intermediate portion 94 is bent overperpendicularly from one side of section 90 between its outer ends, andxed contact supporting arm 96 is turned over from the upper side 98 ofportion 94 (as shown in FIG. 12) to extend back generally toward themiddle of but in front of section 90. (See also FIG. 7.) Arm 96 is thusperpendicular to section 90 and portion 94, and it has a contact button100 `extruded into an aperture formed on the end 102 thereof to matewith a contact button 70 of an associated movable contact blade. The xedcontact terminals of the switch unit which support contact buttons ltltlare positioned against the inner side of a lower wall of housing 4(opposite to the wall which the movable contact terminals are adjacentto), as shown in FIG. 8, with sections 94) of these terminals disposedin generally coplanar fashion, and contact buttons 100 facing outwardlyto engage their mating movable contact buttons. The movable contactblades of my switch are all spring biased upwardly so that the free endwhich carries contact button 70 tends to move away from cover plateV12.. When positioned in my switch unit 2, fixed contact buttons 1410thus serve to cooperate with their mating movable contact buttons 70 toprovide a plurality of pairs of contacts which are normally closed(i.e., spring biased to a contacts closed condition).

To provide a second type of iixed contact in my irnproved multiplepushbutton switch unit 2, and substantially reduce the number ofreciprocating sliders required to control a relatively large number or"movable contact blades, on fixed contact terminals 36c-36f, and 36k, Ihave mounted llexible contact 104. (See FIG. 8.) These contacts 164 arearranged on fixed contact terminals 36e-3612 and 36kf(as shown in FIG.8), for cooperation with movable contact blades 60C-6W, and 66k. As bestseen in FIGS. 7 and ll0, flexible contact 104 comprises a dat supportingportion 106 with a rectangular slot 168 formed therein, and flexiblecontact portion 110. Contact portion 110 extends angularly fromsupporting portion 1%, having a curved contact surface 111 adjacent itsend for engaging the underside of its mating movable Contact button 70(as shown in FIG. 4). Supporting portion 106 of each contact 104 isafiixed to one of the terminals 36o-3612 and 36k by means of slot 108which receives a pair of lanced projecting fingers 112 of the terminalblade 114 in the same manner as previously described for terminalV3'7110 of FIG. 1l, fingers 112 being swaged to overlap the side edgesof the slot and thus secure flexible contact 104 to the terminal.Terminal blades 114 of the terminals 36e-36j, and 36k are positioned, asshown in FIG. 8, against the inner side of the same lower wall ofhousing 4 as blade sections 9i) of the other fixed contact terminals.The curved contact surface 111 of each fiexible contact 104 thusunderlies the free end of an associated movable contact blade (as viewedin FIG. 9). Movable contact blades 60C-6M, and 641k are'normally biasedupwardly and away from cover plate 12 (as illustrated by blade 60k inFIG. 4), as are all the other movable contact blades. Flexible contacts1494 thus serve to cooperate with their mating movable contact blades toprovide a plurality of pairs of mating contacts which are normally open(i.e., spring biased to a contacts open condition). Flexible contact 104pivots about its supporting portion 196 when its associated movablecontact blade is closed thereupon, to provide overtravel for theflexible contact. This overtravel is important in compensating forvariations in the positions of the cooperating movable contact bladewhich are introduced by manufacturing tolerances.

It will thus be seen that my improved multiple pushbutton switch unit 2has two different types of'matingcontact pairs therein, i.e., pairs ofcontacts which are normally biased to a closed condition ('eQg., blade60a, 'which is normally biased into engagement with contact button 130of fixed contact terminal 36a) and pairs of contacts which are normallybiased to an open condition (e.g., blade 60k which is normally biased,away from flexible Contact 104 of fixed contact terminal 36k). Bycombining these two types of mating contact pairs in my switch unit Z, avery large number of movable contact blades may be effectivelycontrolled by a substantially reduced number of sliders. To achieve thisbeneficial result, and thus enable my switch to control a relativelylarge nurnber of circuits by a relatively small number of reciprocatingsliders, certain of the sliders A-E have been combined to controlcertain of the movable contact blades yin my switch in an improvedmanner which shall now be described in detail.

My improved switch unit 2 has -been designed to provide the typicalswitch pattern shown in Table I.

Table I indicates the circuits which are to be opened j and closed by aswitch such as my multiple pushbutton switch unit 2, with an Xrepresenting each switch position requiring a circuit to have itscontrolling contact closed, and an O representing each switch positionwhere it is required rthat a circuit have its contacts open ordisengaged.

In designing multiple pushbutton switch units of the type illustrated inthe aforementioned Andrews Patent No. 2,431,904, the number of circuitsand the number of switch positions have been heretofore low enough sothat three, four, or ve sliders have usually been enough to actuate therequired movable contact blades. The sliders in these prior art switcheshave been arranged to actuate or cam contact pairs of one type, such asnormally closed contacts, to either an open or a closed condition.

8 TABLE I Typical Switching Pattern Switch Positions Circuit O O O O X OX O 0 O X O X O O O O O X X O X X X X X X X X X X X X X X X X X O X X XO X X X X X VX X X X X X X X X X X O O O O X X O O O X X X X X O O X X XO O X O X X X X X O O X O X O X X O O X X X X O X O O X X O O O O X O OO O O X X O O O X X X X X X X X X O X X X X X O O X X X O O O O O O O OO O X X X X X X X X Where, X-controlling contacts Closed, andO-eontrollng contacts Open The determination of the slider pattern insuch switches has been arrived at principally by trial and errorprocedures, with certain rules serving as tentative guides. Forinstance, as one of these rules, it is well known that movable contactblades of circuits having directly opposite switching patterns may becontrolled by forming appropriate cam surfaces on the same slider andreciprocating the slider in opposite directions (such as right and left)to control the respective circuits. In addition, another rule Well knownin the art is that the movable contact blades of circuits which areidentical in pattern may also be controlled by the same slider whenappropriate cam surfaces are formed on the slider and it is reciprocatedin any one direction (such as right or left). On the other hand, it isalso well known that the blades of circuits whose switching patternrequires them to be closed simultaneously in any switch position cannotbe controlled (i.e., actuated) by cam surfaces formed on the same sliderunless these circuits are identical in their switching pattern. Anexample of such circuits which cannot be controlled by the same sliderdue to difference in switch pattern is circuits c and d of Table I.Applying the above-mentioned general rules which are well known in 'theprior art, to the typical switching pattern set forth in Table I above,the opposite and identical circuit switch patterns which are shown inTable II are observed.

TABLE II Opposite and Identical Circuit Switching Patterns SwitchPositions Circuit g O O O X X O O O X X Opposite )3% )(2 g (X) O O j 0 XOpposite {nl O X 0 0 O O O X X O O X O X X O O X X X sassarese O p OOpposite {g O O X X X X X X X X Same X o X X X X X o o X o X 0 X X X X XO O X Same {11 o o X X X X X X X X q 0 0 X X X X X X X X Where,

X-controlling contacts, Closed, and O,--controlling contacts Opentrolled by a single slider, providing such an approach has been found tobe otherwise desirable in designing the multiple pushbutton switch unit.In addition, the circuit pairs and 0, and "n and q each comprise anidentical circuit switching pattern. These last mentioned circuit pairstherefore may be controlled by the same slider in a multiple pushbuttonswitch unit. In now applying the above-discussed general rules fordesigning sliders of a multiple pushbutton switch, according to theprior art practise of using all normally closed movable contact bladeswhich are cammed open by the cam surfaces of the sliders, the sliderarrangement of Table III would thus be typical for my pushbutton switchunit in order to satisfy the switching pattern described in Table Iabove.

In designing multiple pushbutton switch units, Table III represents whatis known as a Slider Arrangement Chart. The two separate columns on theright side of Table III are often referred to as the left-right chart.To determine the slider structures and pattern for controlling therequired circuits, the left-right chart is set up iirst, with circuitletter designations being arbitrarily placed in either the left or rightcolumn of this chart alongside of the slider which is to be designed tocontrol the particular circuit. The column in which the circuit letterdesignation appears then denotes the direction, i.e., left or right, inwhich the slider is to move to cam the circuit controlling blade open.

TABLE III Typical Prior Art-Slider Arrangement Chart both appearancesbeing alongside of slider X. This means that it has been arbitrarilydetermined that slider X should control circuit p by movement of sliderX to the left (to cam blade 60p to its contacts open condition), andcircuits 11" and "q should both be controlled by slider X by movement ofslider X to the right (to cam blades clin and 6tlg to their contactsopen condition). It should be recalled that circuits n and q haveidentical circuit switching patterns and therefore can be controlled bymovement of the same slider in one particular direction, while circuit phas a switching pattern directly opposite to that of circuits n and qand therefore can be controlled by movement of slider X in a directionopposite to that direction which controls circuits n and "q. Circuitsb-f, j-m, and 0, have all been arbitrarily positioned in the left-rightchart of Table III in like manner, using the same procedure as describedfor the circuits "a, "g, "h, 11, "p, and "qf The left-right chart ofTable III may then easily be used as a base for developing the remainderof a typical slider pattern and arrangement, which, according to theprior art, would effectively control the circuits ah, and j-q of TableI. For example, since circuit a is to be controlled (i.e., cammed open)by movement of slider I to the right, and circuit "a must be closed onlyin switch positions 5 and 7, an upper case and h have been determined asdirectly opposite in circuit switching pattern and therefore they may becontrolled by the same slider. As a further example, it is noted thatcircuit "p appears in the left column and cir- Switch Positions Slider'4 5 f 6 7 8 9 10 Left Right Ra L Ru L Ra R Ra a Lb Lb Lb Lb Lb R R b R RR R R R R c R R R R R Ld R a R R R R R R R e R R R R R R Lf j Lh Lh RsRe Re L11 Lil h g Lm Lm Lm Lm Rio Ri Lm m jo L1 L1 Rk Rlc Ll L1 Ll l IcLD Ln Lv Lr LD Lp Ln p nq Where,

Numerals L10-switch positions achieved by depression .of

pushbuttons of pnshrod pairs Roman numerals I-Xs1ider letters R cammingmovement of slider to Right aetuattes switch contact pair( s) L-carnming movement .of slider to Lent actuates switch Contact pair(s)Lower case letters a-h, and j-q-ci1'cuit designations Super-scripts(e.g., a, b, o, etw-circuit oarnmed Open by designated Right or Leftmovement of slider. For example, in the left-right chart, it will benoted R is positioned alongside of slider I underneath each that circuitdesignation a has been placed in the right switch position whereincircuit "a is to be open, to decolumn alongside of slider I. This meansthat it has note that movement of slider I to the right at thatparticubeen arbitrarily decided that slider I should be designed larswitch position cams movable contact blade 60a to control the circuitdesignated (1, by movement of (which controls circuit a) from itsnormally closed to slider I to the right, i.e., cam movable contactblade 66a its contacts open condition. To conveniently further (whichcontrols circuit "a), to a contacts open condiillustrate on the chart ofTable III that the circuit a tion by movement of slider I to the right(as viewed in is controlled by movement of slider I to the right, andFIG. 8). As a further example, it will be noted that 11'1 which switchpositions this occurs, a superscript "a has circuit designation gappears in the right column and Pfhplad 1n falsed POSltlOn USO the right0f the circuit designation "h appears in the left column, with R 1U eachPOSIPH Where the Clfcult conffollmg mlya: both of these designatedcircuits h and g being alongme Contact b1ade-1s t0 be Pam-med Open- Thelette L side of slider VII. This means that it has been arbitrarily 1Splaced 3 l0n-551de of Shder I nder SWltCh POSIOUS decided that sliderVII should control circuit h by and 7 to-md1cate that. movement ofslider I to the left to o am fr tg dcotactts, Opefn onlttlilitmftf Slestion due to the biasing thereof. This movement of s M d as merg Orfhc lb1 d ty. t slider I to the left has not been designated to control of Sher V: to t e ng t o Cam a le g o lis (E9n ft any of the requiredcircuits, and therefore no superscript open condition). It should berecal ed that circuits g 70 appears to the right of the Lia alongsideSlider I for the positions 5 and 7, thus indicating that movement ofslider I to the left in positions 5 and 7 has no actuating eiect on anyof the circuits. The full slider pattern for sliders II-VI, may then bedeveloped in a similar manner as described for slider I.

Turning now to slider VII, it will be seen from the left-right chart,that movement of slider VII to the left has been arbitrarily selected tocontrol circuit h. It is noted that circuit h, in accordance with therequired switching pattern of Table I, is -to be opened in switchpositions 4, 9, and lil. To indicate that circuit "h is to be opened bymovement of slider VII to the left in these positions, an L11 Iis placedalongside of slider VII under switching positions '4, 5, 9, and 10. Itwill now be understood that movement of slider VII to the right occursin the other switch positions (1, 2, 3, 6, 7, and `ii), which movementhas no camming effect upon the blade controlling circuit h and thusallows it to return to its normally closed condition. Considering thenlfurther Ithe use of slider VII, it is noted that in pursuance of thepreviously discussed general rules of slider usage, circuit g (which isopposite to circuit h in switching pattern) appears in the right columnalongside of slider VII. This means that circuit g is to be controlledby movement of slider VII :to the right. An Rg is thus placed alongsideof slider VII in the columns under switch positions 1, Z, 3, 6, 7, and8. This indicates a fuliillment of the requirement in the switchingpattern that movable contact blade 60g is to be cammed open in switchpositions 1, 2, and 3, and 6, 7, and 8. IIn like manner, the remainderof the slider pattern and arrangement for sliders VIII, IX, `and X, hasbeen developed by placing an R `or L alongside of each slider under theswitching position in accordance with the direction (i.e., lef-t orright) that the particular slider is to be moved at that switch position:to cam the appropriate circuit controlling blade open, with theappropriate superscript appearing in a raised position just to the rightof the R or L to indicate that circuit which is to be controlled by suchdirectional movement of the particular slider in that switch position.

The typical prior art slider arrangement chart of Table III thusindicates that a minimum of ten sliders in all (sliders I-X) arenecessary to satisfy the circuit requirements o-f Table I. In furtheranalyzing the slider arrangement of Table III, it might be `consideredby those skilled in the art, that the total number of circuitcontrolling sliders could possibly be reduced by examining the sliderpattern of Table Ill to determine whether or not a combination ofsliders can be used to control a particular circuit and, if so,combining such sliders to cam the controlling contact blades open. Forexample, circuit l (lower case L) is required to be open in pos-itions2, `4, 5, 8, 9, and 10. Slider VII, by movement to the left, could holdcircuit l open in positions 4, 5, 9, and 10, and slider VIII, bymovement to the right, could control circuit l for positions 2, A8, and9. By forming appropriate camming surfaces on sliders VII and VIII, acombination of sliders which have already been otherwise used could thusbe achieved for controlling circuit 1. It should be noted, however, thatit is important in combining sliders yfor controlling a circuit, thatnone of the -sliders which are combined may hold a circuit open in anyother position (by movement of the slider in the same direction) thanthose which are required -for the circuit which is to be controlled bythe combination. Slider VII, to the left, and slider VIII, to the right,satisfy these requirements, since slider VII moves to the left only atpositions 4, 5, 9, and 10, and slider V-III moves to the right only atpositions 2,3, and 9. Unless the slider satisiies such requirements, itmay not be combined to control an additional circuit. Looking furtherfor any combination of sliders which may satisfy the requirements forthe complementary circuit of circuit "l, circuit k, it is noted thatcircuit "k is open in positions A1, 3, 6, and 7. Slider III, to theleft, may be used for position 1 in controlling circuit k, and slider Vto the left, may be used in position 3 for controlling circuit k, butthere is no slider with a pattern suitable in positions 6 and 7 vforcontrolling -circuit k. It is therefore concluded that no beneiit may bederivedby the aforementioned combination of sliders serving to controlcircuit 1, since its complement, circuit k, requires a separate slider,anyway, for the control thereof. It is also noted that circuits c, "d,6, and ff having only one open position, cannot benefit by theapplication of such a technique. It has thus been found, therefore, thatin accordance with the practice of camming one type of circuitcontrolling contacts open, control of the circuits listed in Table Irequires ten sliders in number.

Turning now to an important aspect of my invention, which concerns theslider arrangement and pattern in my multiple pushbutton switch unit 2,I have found that by using normally open contact blades which are cammedto a closed position by the lreciprocating motion of certain of thesliders, combinations of sliders may be used in a new and improved wayfor controlling certain circuits. ,More specifically, in my multiplepushbutton switch unit 2, -it has thus been found that by using cammedclosed movable contact blades in conjunction with the sliders requiredto control these blades, and also using cammed open movable contactblades which are actuated by combinations of the same sliders, the totalnumber of sliders required to control the -various circuits outlined inTable I may be reduced Afrom ten to Iive. To explain more particularlyhow this has been done, attention is momentarily reverted to the TypicalPrior Art Slider Arrangement Chart shown in Table III above. By omittingthe sliders required to control circuits c, d, e, L k, and l (i.e.,sliders III, IV, V, VI, and IX), the slider arrangement shown in TableIV may be obtained.

It should be noted `at this point that the slider pattern of Table IVprovides complete mechanical interlock for the pushbutton action of myswitch unit 2, since the pattern of Rs and Ls for each of the tenswitching positions, is not repeated elsewhere. lIn any multiplepushbutton switch of the type exempliiied by the aforementioned AndrewsPatent No. 2,431,904 which includes working surfaces cooperating withthe pushrods to provide the mechanical interlock for the switch, whenthe pattern of Rs and Ls is different in every switch position, theswitch has been provided with complete mechanical interlock for thepushbutton action.

Turning attention now back to the switching patterns of the circuits c,61, e, and f of Table I, it should be initially noted that thesecircuits, which are not now controlled by yany of the sliders in TableIV, are each characterized by being open in only one switching position(e.g., circuit c is only openl in position 1).

TABLE IV Intermediate Improved Slider Arrangement Chart 13 Where,

Numerals L-switch positions achieved by depression of pushbuttons ofpushrod pairs Roman numerals IX-slider letters 14 nient for my multiplepushbutton switch unit 2. The reference identification ofthe fivesliders I, II, VII, VIII, and X, has now been changed to lthe upper caseletters AE to represent the iinished sliders (as shown in FIG.

K Cammiug movement of slider to Right actuates 5 13) which have beenconstructed in accordance with my switch Contact pair(s) invention. Incorrelating the antecedent sliders of Table L camming movement of sliderto Left actuales IV with those of Table V, it should be noted thatslider Switch Contact pair) -A is derived from slider l, slider B isderived from slider Lower Case letters u h `and j qwcircuit designationsII, slider C is derived -lfrom slider slider D is derived Suprscpts(e'gw a, b c etcJqCircuit cammed Open 10 from slider VII, and slider Eis derived from slider VIII. by designated Right or Left movement ofSlider. 4Considering `further the arrangement of Table V, it will -benoted that Rs and Ls have been used to designate y nyuuvntlon ead O fthese cifcugs mali bl'demcleny directions of camming movement of theslider to the right 1. of ner as as #een previousy escri e The ower casegflcuf 1f tg bel ldpen'b More parlcufl'ay kmglst letter superscriptswhich appear a raised. position to ai cluiin c, w'ic mis) o e operi ogylsl 1011 d the right of the Rs and Ls indicate the circuit which p dm'ttleme fl ;,lbn xlamnglon 1S en gli? f is cammed open by designatedright or left movement of a llbialion of gis nde R, It e Purpos O( n mg20 the slider cam surface in that particular switch position clusivel inSwitch sition S1 maw in y 'e-ex' (in the same manner as'deseribedpreviously lfor Table tion mayy Sometimespinvolve a'll o lesgev) 81?162g III). For example, it will be noted that at switch posi- A i Y,"tion 4, for slider B, Lb appears. This designation dglylisg tfr sbgte'lfugldalsgmtlt denotes that in switch position d, movable contact bladesliders in switch position .1, it may be found that slider gleobo llloggelglwlnem or posltlomng vnl to the left and Slider X to the rightfurnishes the In further analyzing Table V it will be noted that cero es an s an are un erlined or emp asis (e.g. VIII and X in switch osition1 with the combination of .i Rs and Ls for the saline two sliders in allof the other ERM .for shder C. m Position 1) Thls def'slgnauqn (if nineswitching positions besides switching position i it imderhnedsuperscnpts Indicates. that a pamcular-c1rcult Should be nted that thesame combination as provied Iidentified by the letter designation thatis underlined or at switching position i1 does not @appear It may thussubscored is allowed to open by right or left movement be establishedthat when slider VIH mov'es to the right of associated slider camsurfaces on two or more sliders or slider X moves to the left, movementof these sliders m thzt Sytvlltch osmon qrnlsthne. astregolsly in theirpredetermined respective directions will cam mo-'vcusie. 1 as .een ascerai e. a m .e rs SW1 C able contact blade `60e to a contacts closedcondition. posltlonfwhen Shder. C (denva'tive from shder x) moves Itwill thus be seen, that the only switch position in which to the rightand Shder E .(demvauve. from .shder VIII) movable contact blade y60C maymove to its contacts open movs to Fhe iefti in Xduslve Pattern 1SObtamed for con' `condition is in the rst position. 'In all the otherswitch 10 troumg C11-cult C (l'ej allowmg blade we to Opern' positions,blade 60e is cammed to a contacts closed con- The subscofd supescnpt'gthus @pears tf) the left of dition by the sliders vin and X. Toiiiusi-rate in tabuiar the R for Slldef C 1110 SWltCh POSIQOH 1 (Le-iERfq l, form the manner in which combinations of sliders may afld alsot0 the left 0T the L fol' Slldef E at POSlflOn 1 be used to control theimuits cj dj e L kj (i.e., C kLm), to indicate the controlling functionsof and "1, attention is now directed to Table V. these sliders.

TABLE V Slider Arrangement Chart 0f My Switch Unit Switch Positionsslider i 2 3 4 5 6 7 8 9 1o Left Right Ra R R L- Ru L- R RH Ri a Lb 3R*Lb Lb Lb Lb Lb dR fR def b C Rw RM1 Lv Lv Lv Lv Lv LD Lv Lv gp ngi D R1Re me Lhl Lhl R kRz Rz Lhl fLhl @nl l E grim Rua Lm Lm Lm kLm gLm R510Rim Lm gm ,engl

Where, Turning now to the left-right chart of Table V, it

Closed which is allowed to open by designated Right or Left movement ofslider.

Table V represents a tabulation of the slider arrangewill be noted thatthe subscored superscript g now makes an appearance there, in the leftcolumn-alongside of slider C, and in the right column-alongside ofslider E. vThis indicates that the combination of sliders C and E isbeing used to cam blade 66e closed by movement of slider C to the left,and by movement of slider E to the right. The positioning of theenclosed lower case letters in the left and right columns of Table Vrespectively thus indicates that the `circuits identified by theseletters are cammed closed by right or left movement of the associatedslider cam suriface(s) in the manner designated.

Continuing further with a description of my improved means `forreducingr the number of sliders required to control the circuits ofTable l, it will be noted that circuit d thereof is -characterized byhaving its contacts open only in position 9. In analyzing the R and Lpattern for switch position 9, a combination of Rs and Ls that occursonly in switch position 9' is then sought in the same manner .aspreviously described for circuit 0. Such an analysis indicates thatslider B, to the right, and slider E, to the right, will furnish thedesired exclusive pattern. It is then established that slider B, to theleft, and slider E, to the left, will cam movable contact blade 60d to aclosed circuit condition. To represent this determination, the subscoredsuperscript Q appears to the left of the R for sliders B and E in switchposition 9. The subscored lower case letter Q is also placed in the leftcolumn of the left-right chart of Table V opposite the sliders B and Erespectively, to indicate that movement of sliders B and E to the leftwill cam blade 60d to a closed circuit condition (-Which occurs in allswitch positions except position 9).

Turning now to circuit e, it is noted from Table I that circuit e isopen only in switch position 3. An examination of the R and L sliderpattern Ifor the i-ve sliders is then again made in search of acombination of Rs and Ls that occurs only in the third position. It isfound that slider B, to the right, slider C, to the left, and slider D,to the right, -furnishes the desired exclusive pattern. It is thusestablished that slider B, to the left, slider C, to the right, andslider D, to the left, will cam movable contact blade 60e closed. Toindicate the fact that sliders B, C, and D, have been chosen forcontrolling circuit e in this manner, the underlined superscript e hasbeen placed to the left of the R of slider B, the L of slider C, and theR of slider D, all of Which appear in switch position 3 of Table V. Tofurther indicate the arrangement of sliders B, C, and D for maintainingcircuit e closed in all other positions except position 3, the subscoredlower case letter e is placed in the left column alongside of slider B,in the right column alongside of slider C, and in the left columnalongside of slider C.

Considering now circuit J2 and referring again to Table I, it is notedthat circuit f is open only in switch position x10. By examining the Rand L slider pattern tor the sliders for the purpose of iinding acombination of Ls and Rs that `occurs only in position 10, it is foundthat slider B, to the right, slider D, to the left, and slider E, to theleft, furnishes the desired exclusive pattern. It is thus establishedthat, movement of slider B', to the left, slider D, to the right, andslider E, to the right, Will cam movable contact blade 60f closed. thatthe only position in which circuit f may be opened is in the tenthposition. To indicate this on Table V, the subscored superscript iappears under switch position 10 to the left of the R of slider B, the Lof slider D, and the L of slider E. To further indicate on the leftrightchart that circuit is to be cammed closed by the movements of slider Bto the left, and slides D and E, to the right, the subscored lower caseletter f is placed in the left column alongside of slider B and in theright Kcolumn alongside of sliders D and E, respectively.

In now rendering further consideration to circuits k iand l (as`outlined in Table I), an `analysis has previously been made of thepattern tor circuit 1. This previous :analysis of circuit l indicatedthat this circuit is open rin positions 2, l4, 5, 8, 9, and 10, and thattrom Table "III, slider VII, to the left, could hold it open inpositions `4, 5, 9, `and 10, and slider VIII, to the right, couldperform this function for positions 2, 8, land 9. The =R and L patternsof sliders D and E (Table V) are derivative respectively trom slidersVII and VIII (Table III), Iand therefore the sliders D and E may becombined in the same manner to control circuit "l. While it was decidedthat the sliders VII and VfIII lof Table -III could be used in suchcombined fashion to control circuit 1, it was also found that by usingthe prior art approach, no combination could be obtained which wouldsatisfy the requirements of the complementary circuit k. By applying myinvention, in analyzing circuit k, for the purpose of nd- It is obviousthen ring a combination of sliders that would open circuit k inpositions 1, 3, 6, 'and 7 (viewing Table I), an exclusive pattern may befound. By studying the yR yand L slider pattern of 'Ilable V, it isfound ythat slider D, to the right, and slider E, -to the left, providean exclusive combination which appears only in the switch positions 1,3, 6, and 7, and in no other switching positions. Thus, thecomplementary circuits "k and l may each be controlled by combining thesliders D and E. To illustrate that circuit "l is to be cammed open inpositions 4, 5, 9, and 111 by slider D, the plain superscript l isplaced to the right of the L in these switch positions in Table V(alongside yof slider D) 'and it is also placed to the right of the Rappearing in switch positions 2, 8, and 9 (alongside of slider E), :toindicate the controlling function for sliders D and E. In the samemanner previously described for circuits cammed open, appropriateentries have also been made in the left-right chart of 'Iable V toindicate the `direction of movement of sliders D land lE to controlcircuit 1. To illustrate in Table V the controlling lfunctions ofsliders -D and E for circuit "k (which is cammed closed), the subscoredsupe-rscript E is placed to the left of the R alongside of slider D inpositions 1, 3, `6, and 7, Iand to the ileft of the L alongside ofslider E in positions 1, 3, 5, and 7. The underlined lower case circuitletter 1 0 has also been placed in the left column ,alongside of sliderD and in the right column alongside of slider E to indicate thatmovement of slider D to the left `and movement of slider E to the rightwill keep circuit k cammed closed in all of the switching positionsexcept 1, 3, 6, and 7.

It will thus be seen that by virtue of my invention, there has beenprovided ian improved multiple pushbutton switch unit 2 having aneicient means for controlli-ng the circuits a-h, iand j-"q (16 circuitsin all) by means of only tive sliders. This result has been obtained bythe use of movabie contact blades which are cammed closed by certainsliders in some of the switch positions and allowed to open by movementof yan exclusive combination of sliders in `other switch positions. Itwill be obvious to those skilled in the art that numerous othercombinations and arrangements of slider patterns might be obtained usingthe same principles 'and structure which I have heretofore described,with equally beneficial results.

Turning now to la further explanation of my multiple pushbutton switchunit 2, it will be noted that `as shown in FIG. 13, I have `alsoincluded two other sliders F `and G. Slider F is designed to serve as adetent, or pushrod controlling slider and -slider G has been constructedto co'- `operate with `detent sliderrF and to serve as a momentary fandbutton return slider for the switch unit. More particularly, as shown inVFIG. 13, detent slider F includes a series `of spaced speciallyconstructed Working recesses 121 extending inwardly trom its upper edge122 land momentary .slider G includes [a series of spaced recesses 123rwhich are identical in configuration to recesses i121 but are ydisposedin a reverse longitudinal direction. The sliders F and G ,also havelongitudinally extending projections 124 Iand 126 (as shown in FIG. 13)which receive one en'd `of .associated compression springs 12B and 136i.The other end of each compression spring 128 and 130 is supported bytransverse bracket 132 which is positioned athwart and adjacent theclosed end of base l8 to continuously bias both lof the sliders -F and Gto the right (las shown in FIG. 8).

To facilitate an understanding of the operation of the detent yandmomentary sliders F 'and G respectively, fattention is drawn -to FIG.14. The detent slider F and the momentary slider G are both there shownin fragmentary view, with the momentary slider G being positioned infront of the `detent slider F. lFor purposes of illustration, the pairsof pushrods 41 and 50 are da-granmiatically shown, with the pushbutton`62 that controls the pushrods 41 being in an intermediate ldepressedactuating position. With pushrods 411 in the position shown in F-IG. 14,pushrods 54), which would be located at the other end of the switch are,of course, held in their outermost position by means of the biasingeffect of `associated spring 66 (as shown in FIG. 2) on the controllingpushbutton. In addition to the outward biasing force `of spring 66,however, angular edge sections 121a of adjacent recesses 121 of thedetent slider F :also engage the actuating portions 5 6 of the twopushrods l50 to urge them or cam them toward their uppermost positionsby means of the spring biasing force applied by compression spring 12Sto slider F. (See FIG. 8.)

When pushbutton 62 controlling pushrods Stl is depressed (i.e., movedfrom its position shown in FIG. 14 to its position shown in PIG. 15),the biasing force to the right applied to slider F by compression spring128, initially provides a resisting force to the depression of thepushrods by means of the engagement of angular sections 121a of the tworecesses 121 which are associated with the pushrods 50l with theirpushrod actuating portions 56. This resisting force provides an eicientmeans ttor controlling these pushrods during their initial downwardmovement. When the pushrods 541i' .are `further depressed, as shown inFIG. 15, the compressive force applied to detent slider F by compressionspring 1128 is overcome by the manual pressure exerted upon thecontrolling pushbutton 62. Slider F is then moved to the left, to theposition where it is shown in FIG. 15. As p-ushrods 50 are thendepressed further toward their extreme depressed position, as shown inFIG. 16, actuating portions 56 pass points 12111 of the slider F. SliderF thus snaps to the right due to the force of spring 1128 to itsposition as shown in PIG. 161. When pushrods 5% move from their positionin FIG. 15 tothe extreme depressed position of FIG. 16, actuatingportions 56 .thereof also cam momentary slider G to the left momentarilyfrom its position as shown in FIG. 15, to hold slider G against the:compressive biasing force of its spring 130 in the position shown inFIG. 16. When pushrods 5G are in their extreme depressed position, asshown in FIG. 16, rods 41 have then been moved back to their outermostposition and the camming section r of slider G moves to the left toallow normally closed movable contact blade 6dr to make contact with itsmating iixed contact. When the pressure exerted `upon pushrodsV 5t)` isthen released, momentary` slider G moves back to the right, to theposition shown in FIG. 17, thus forcing the pushrods 50 outwardly towhere they are shown by `angular sections 123C. Pushrods 50- are then intheir intermediate contact actuating position and are locked in thatposition by means of curved points 12119 of the recesses of detentslider F.

It will thus be seen that the cooperation between the detent slider Fand the momentary slider G of my multiple pushbutton switch unit 2provides for eficient control of Ithe movement of the pairs of pushrodsi1-Stii during the reciprocation thereof between their depressed andouter (normal) positions. In addition, momentary slider G is aneliicient means for returning depressed pushrods to their outer (normal)positions while at the same time providing momentary contact action formovable contact blade `6th' during the depression of any pair ofpushrods. The particular construction of sliders F and G and fthebiasing arrangement for them in my switch comprises the invention `ofStewart A. Woodward and this construction and arrangement are described:and claimed in his aforesaid copending application Serial No. 42,815.

Turning now to a further explanation of the operational aspects of mymultiple pushbutton switch unit 2, to il- -lfustrate the operation of atypical movable contact blade which is cammed open, I have chosen bl-ade60a, which is controlled by slider A. FIG. 18 shows the pushrods 41diagrammatically as they are positioned with respect to their associatedworking surfaces 1 of slider A when the pushrods 41 are maintained intheir intermediate depressed actuating position. For purposes ofsimplification, a section of only slider A has been shown in FIG. 18,since slider A is eiiectively responsible tor the actuation camsurfaces.

of lthe movable contact blade sila. When slider A is in this position,an outwardly extending section oi the camming surface A-a overliesmovable contact blade dita, as shown in FIG. 18, and holds it open fromengagement with its mating iixed contact against the normally closedbiasing force of blade 60a. When pushrods 41 are in their intermediatedepressed position (as shown in FiG. 18), pushrods i5 are in their outeror uppermost position with respect to the working surfaces 5 of sliderA. When pushrods 45 are then depressed to their position in FIG. =19,they engage the diagonal edges of the working surfaces 5 to move sliderA to the left. Movement of the entire slider A thus occurs, and thediagonal edges of working surfaces 1 of slider A engage the pushrodactuating portions 56 of pushrods 41 to move pushrods 41 back to theiruppermost position (as shown in FIG. 19). Movable contact blade 6de thusenters an inwardly extending recess section a of cam surface A-a and isallowed to close upon its mating xed Contact (not shown). All of theother movable contact blades of my switch -uni't 2 which are cammed open`are operated in a similar manner to that described for the pushrods d1.

Considering now the operation of the movable contact blades of my switchunit 2 which are cammed to a contacts closed position, in FIG. 2G, thesliders C and E are represented in fragmentary fashion, along with blade69C. The sliders C and E have been previously selected for controllingmovable contact blade 6de, which is to be open only in position 1. Withpushrods 42 thus depressed, as schematically represented in FIG. 20, theleft ends oi' the sliders C and IE are adjacent, and an outwardlyextending section of cam surface E-c (of slider E) holds or cams movableContact blade 6de to a contacts closed position in engagement with itsassociated fixed contact.

When pushrods 41 in FIG. 20 are depressed to their intermediateactuating position shown in FIG. 2l, slider E lis moved to the left bymeans of the engagement of actuating portions S6 of the pushrods 41 withthe diagonal working surfaces 1 of slider E. Movement of slider E to theleft, to the position in which it is shown in FIG. 2l lalso causespushrods 42 to be moved outwardly by means of the coaction of diagonalworking surfaces 2 of slider E therewith. The cam .surface E-c alsomoves to the left so that it cooperates with cam surface C-c to form analigned recess which allows movable Contact blade @c to move upwardly byits spring biasing force to open the pair of contacts controllingcircuit c. It should be noted at this point, that the only position inwhich cam surfaces C-c and E-c may cooperate to allow movabie Contactblade dile to open is in switching position 1. The reason for this, aspreviously described, is that only in switch position 1 will thisparticular combination of movements by sliders C and E occur.

FIG. 22 illustrates the relative positions of sliders B, C, and D, whenpushrods i3 are depressed. It will be recalled that sliders B, C, and Dhave been designated to control circuit e by camming movable Contactblade 6de open in position 3. In FIG. 22, slider B is positioned in theforeground, slider C is positioned behind it, and slider D is positionedin the background behind slider C. When pushrods 43 are depressed, thecam surfaces B-e, C-e, and D-e (as shown in FIG. 13), cooperate to allowmovable contact blade title to move into an over-all aligned recessprovided by the cooperation of these three When movable contact bladediie moves into this indented recess, it opens circuit e. In all otherpositions besides switch position 3, the combination of movements ofsliders B, C, and D, which is obtained in position 3 is not achieved,and therefore, movable contact blade @tlc is cammed into closedengagement with its associated xed contact in the same manner aspreviously described.

FIG. 23 illustrates diagrammatically the circuit arrangement of theterminals of switch 2. Only the terminals which are to be connected toexternal leads have been identified byy reference numerals in thisfigure. It will be understood by those skilled in the art that thearrangement of the various terminals and the selection of externalbridges 144i (FlG. 2) have provided this switch circuit configuration.Blade dits is a dummy blade in switch 2, since it is not actuated.

It will now therefore be seen that my new and improved multiplepushbutton switch unit 2, as herein illustrated, provides an efiicientand advantageous means for controlling a large number of circuits. ltshould be realized that by combining sliders in the manner that I havedisclosed, numerous other arrangements of sliders may be obtained forcontrolling circuits having various switching requirements. Further, itmay be preferable to utilize any number of combinations of sliders inaccordance with the circuit requirements which are to be satisfied by aparticular multiple pushbutton switching unit. It should therefore berealized that certain aspects of my invention may be incorporatedefficiently and beneficially in other various types of pushbutton switchapplications.

While in accordance with the patent statutes I have described what atpresent is considered to be the preferred embodiment of my invention, itwill be obvious to those skilled in the art that various changes andmodifications may be made therein without departing from my inventionand I therefore aim in the following claims to cover all such equivalentvariations as fall within the true spirit and scope of this invention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

l. A multiple pushbutton switch unit for controlling a plurality ofcircuits comprising a plurality of manually depressible actuators, apredetermined number of longitudinally movable sliders engaged andoperated by said actuators, the surfaces of said sliders engaged bysaidactuators being slanted both for operation by said actuators and forcontrolling the position of said actuators relative to each other, aplurality of switch arms biased in one direction toward a normalposition and being movable by said sliders against their biasing to asecond position, first fixed contact means engageable respectively byselected ones of said switch arms when said switch arms are in saidnormal position, thereby to form a plurality of normally closedswitches, and second fixed contact means engageable respectively by atleast one other of said switch arms when said other arm is in saidsecond position, thereby to form at least one normally open switch andincrease the circuit controlling flexibility of said switch unit withoutincreasing the number of said sliders, said switch arm of one of theswitches engaging at least two of said sliders and being actuated by theconjoint action thereof.

2. A multiple pushbutton switch unit for controlling a plurality ofcircuits comprising a hollow housing, a plurality of manuallydepressible actuators extending into said housing through a wallthereof, a predetermined number of longitudinally movable elongatedsliders arranged in side-by-side relationship within said housing, eachslider having a series of diagonal working surfaces generally inalignment with and distinct from working surfaces in the other sliders,each actuator having an inner portion extending transversely through analigned group` of working surfaces of the sliders to move the sliders topredetermined contact controlling positions, said working surfaces ofsaid sliders being diagonally slanted both for operation by theassociated actuators and for controlling the position of said actuatorsrelative to each other, a plurality of switch arms biased in onedirection toward a normal position and being movable by said slidersagainst their biasing to a second position, first fixed contact meansengageable respectively by selected ones of said switch arms when saidswitch arms are in said normal position, thereby to form a plurality ofnormally closed switches, and second fixed contact means engageswitcharm engaging and being actuated by the conjoint Y action of cam surfaceson at least two of said sliders,

and each of said last mentioned sliders having at least one additionalcam surface engaging and actuating the switch arm of one of saidnormally closed switches whereby said p last mentioned sliders operatesaid normally open switch simultaneously with at least one of saidnormally closed switches.

3. A multiple pushbutton switch unit for controlling a plurality ofcircuits comprising a hollow housing, a plurality of adjacent pairs ofmanually depressible actuatorsV extending into said housing through awall thereof, a predetermined number of longitudinally movable elongatedsliders arranged in side-by-side relationship within said housing, eachslider having a series of adjacent pairs of A coincident diagonalworking surfaces generallyin alignment with and distinct from adjacentpairs of coincident diagonal working surfaces in the other sliders, eachactuator having an inner portion extending transversely through analigned group of working surfaces of the sliders, a pushbutton attachedto the outer ends of each pair of said actuators to move the sliders topredetermined contact controlling positions by depression in unison ofeach pair of actuators, said diagonal working surfaces engaging saidactuators for operation thereby and for returning each previouslydepressed pushbutton to its outermost position upon subsequentdepression of another pushbutton, a plurality of switch arms all biasedin one direction toward a normal position and being movable by saidsliders against their biasing to a second position,` first fixed contactmeans engageable respectively by selected ones of said switch arms whensaid switch arms are in said normal position, thereby to form aplurality of normally closed switches, and second fixed contact meansengageable respectively by at least one other of said switch arms whensaid other arm is in said second position, thereby to form at least onenormally open switch and increase the circuit controlling flexibility ofsaid switch without increasing the` number of said sliders, said oneother switch arm engaging and being actuated by the conjoint action ofcam surfaces on at least two of said sliders, and each of said lastmentioned sliders having at least one additional cam surface engagingand actuating the switch arm of one of said normally closed switcheswhereby said last mentioned sliders operate said normally open switchconcurrently with at least one of said normally closed switches.

4. A multiple pushbutton switch unit for controlling a plurality ofcircuits comprising a plurality of manually depressible actuators, apredetermined number of longitudinally movable sliders engaged andoperated by said actuators, the surfaces of said sliders engaged by saidactuators being slanted both for operation by said actuators and forcontrolling the positioning of said actuators relative to each other, aplurality of switch arms all biased in one direction toward a normalposition and being movable by said sliders against their biasing to asecond position, first fixed contact means engageable respectively byselected ones of said switch arms when said switch arms are in saidnormal position thereby to form a plurality of normally closed switcheswhich are cammed open, and second fixed Contact means engageablerespectively by at least one other of said switch arms when said otherarm is in said second position thereby to form at least one normallyopen switch which is cammed closed to increase the circuit controllingiiexibility of said switch without increasing the number of saidsliders, one of the switch arms engaging and being actuated by theconjoint action of cam surfaces on at least two of said sliders, andeach of said last mentioned sliders having at least one additional camsurface engaging and actuating the switch arm of another of saidswitches concurrently with said one switch arm.

5. The switch unit of claim 1 wherein the normally open switch is openedupon the depression of an associated one of said actuators but remainsclosed upon the depression of all of said other actuators.

6. A multiple pushbutton switch unit for controlling a plurality ofcircuits by movement of switch arms where at least one of said switcharms is in engagement with its mating fixed contact in more than half ofthe switch positions and is open in less than half of the switchpositions, said unit comprising a plurality of manually depressibleactuators, a predetermined number of longitudinally movable slidersengaged and operated by said actuators, the surface of said slidersengaged by said actuators being diagonally slanted both for operation bysaid actuators and for controlling the positioning of said actuatorsrelative to each other, a plurality of contact supporting switch armsall biased in one direction toward a normal position, certain of saidsliders being arranged to cam a first group of said switch arms againsttheir biasing force to a second position, a plurality of said slidershaving cam surfaces cooperating to cam at least one other of said switcharms against its biasing force to said second position, first fixedcontact means engageable respectively by the first group of switch armswhen said switch arms are in the normal position, thereby to form aplurality of normally closed switches, and second fixed contact meansengageable by said one other switch arm when said other arm is in itssecond position, thereby to form at least one normally open switch andincrease the circuit controlling flexibility of said switch unit withoutincreasing the number of said sliders, said plurality of sliders havingcam surfaces cooperating to cam said one other switch arm each havingadditional cam surfaces for camming at least one of said first group ofswitch arms, whereby said normally open switch is operated concurrentlywith at least one of said normally closed switches.

7. The switch unit of claim 4 wherein the normally open switch is openedupon the depression of an associated one of said actuators but remainsclosed upon the depression of all of said other actuators.

8. A multiple pushbutton switch unit for controlling a plurality ofcircuits comprising a hollow housing, a plurality of manuallydepressible actuators extending into said housing through a wallthereof, a predetermined number of longitudinally movable elongatedsliders arranged in side-by-side relationship within said housing, eachslider having a series of diagonal working surfaces generally inalignment with and distinct from working surfaces in the other sliders,each actuator having an inner portion extending transversely through analigned group of working surfaces of the sliders to move the sliders topredetermined contact controlling positions, said working surfaces ofsaid sliders being diagonally slanted both for operation by theassociated actuators and for controlling the position of said actuatorsrelative to each other, a plurality of switch arms biased in onedirection toward a normal position and being movable by said slidersagainst their biasing to a second position, first fixed contact meansengageable respectively by selected ones of said switch arms when saidswitch arms are in said normal position, thereby to form a plurality ofnormally closed switches, and second fixed contact means engageablerespectively by at least one other of said switch arms when said otherarm is in said second position, thereby to form at least one normallyopen switch and increase the circuit controlling flexibility of saidswitch without increasing the number of said sliders, said second xedcontact means comprising at least one flexible contact member that isgenerally V-shaped and has a curved free end which engages a matingswitch arm, said one other switch arm engaging and being actuated by theconjoint action of cam surfaces on at least two of said sliders, andeach,

of said last mentioned sliders having at least one addiswitches.

9. The switch unit of claim 6 wherein the second fixed contact meanscomprises at least one flexible contact member, said member beinggenerally V-shaped and comprising a supporting portion with a slotformed therein to receive cooperating fingers of a supporting terminalblade, and a fiexible contact portion bent over angularly from saidsupporting portion and having a curved free end which engages a matingswitch arm.

10. In a pushbutton switch, a housing, a plurality of actuatorsextending into said housing, a plurality of longitudinally movablesliders arranged side by side in said housing transversely of saidactuators and having working surfaces on their upper edges engaging saidactuators for actuation thereby, said sliders having cam surfaces formedon their lower edges, a plurality of switch arms biased to a normalposition against said cam surfaces and being movable by said slidersagainst the bias to a second position, said switch arms being movable ina plane transverse to that of said sliders, and a fixed contact meanspositioned beneath and engageable by one of said switch arms to form anormally open switch therewith, said fixed contact means comprising afiexible electric contact for a switch, said contact being of thin bladeconstruction and comprising a fiat supporting portion with a slot formedtherein for engagement with a supporting terminal, and a flexiblecontact portion extending angularly from one end of said supportingportion and having a curved free end which serves as a contact surfacefor engaging said one switch arm.

11. A multiple pushbutton switch unit for controlling a plurality ofcircuits comprising a hollow housing, a plurality of manuallydepressible actuators extending into said housing through a wallthereof, a predetermined number of longitudinally movable elongatedsliders arranged in side-by-side relationship within said housing, eachslider having a series of diagonal working surfaces generally inalignment with and distinct from working surfaces in the other sliders,each actuator having an inner portion extending transversely through analigned group of working surfaces of the sliders to move the sliders topredetermined contact controlling positions, said diagonal workingsurfaces engaging said actuators for operation thereby and forcontrolling the positioning of said actuators relative to each other, aplurality of switch arms all biased in one direction toward saidactuators to a normal position, certain of said sliders being arrangedto move longitudinally in first or second opposite directions to cam afirst group of said switch arms against their biasing force away fromsaid actuators to a depressed actuating position, a plurality of saidsliders having an exclusive pattern of longitudinal movement in saidfirst and/or second directions responsive to the movement of one of saidactuators to its depressed actuating position, said plurality of saidsliders having cammed surfaces cooperating with each other for cammingat least one other of said switch arms against its biasing force to adepressed actuating position, first fixed contact means engageablerespectively by the first group of switch arms when said switch arms arein the normal position, thereby to form a plurality of normally closedswitches, and second fixed contact means engageable by said one otherswitch arm when said other arm is in its depressed actuating position,thereby to form at least one normally open switch and increase thecircuit controlling flexibility of said switch unit without increasingthe number of said sliders, said plurality of sliders having camsurfaces cooperating to cam said one other switch arm each havingadditional cam surfaces for camming at least one of said first group ofswitch arms, whereby said normally open switch is References Cited inthe file of this patent UNITED STATES PATENTS Porter Apr. 22, 1902 Z4Andrews Dec. 2, 1947 Williams Aug. 28, 1951 Batcheller Apr. 7, 1953Batcheller Sept. 15, 1953 Dumke et al. Apr. 15, 1958 Vermeulen Mar. 17,1959 Deighton Sept. 20, 1960

1. A MULTIPLE PUSHBUTTON SWITCH UNIT FOR CONTROLLING A PLURALITY OFCIRCUITS COMPRISING A PLURALITY OF MANUALLY DEPRESSIBLE ACTUATORS, APREDETERMINED NUMBER OF LONGITUDINALLY MOVABLE SLIDERS ENGAGED ANDOPERATED BY SAID ACTUATORS, THE SURFACES OF SAID SLIDERS ENGAGED BY SAIDACTUATORS BEING SLANTED BOTH FOR OPERATION BY SAID ACTUATORS AND FORCONTROLLING THE POSITION OF SAID ACTUATORS RELATIVE TO EACH OTHER, APLURALITY OF SWITCH ARMS BIASED IN ONE DIRECTION TOWARD A NORMALPOSITION AND BEING MOVABLE BY SAID SLIDERS AGAINST THEIR BIASING TO ASECOND POSITION, FIRST FIXED CONTACT MEANS ENGAGEABLE RESPECTIVELY BYSELECTED ONES OF SAID SWITCH ARMS WHEN SAID SWITCH ARMS ARE IN SAIDNORMAL POSITION, THEREBY TO FORM A PLURALITY OF NORMALLY CLOSEDSWITCHES, AND SECOND FIXED CONTACT MEANS ENGAGEABLE RESPECTIVELY BY ATLEAST ONE OTHER OF SAID SWITCH ARMS WHEN SAID OTHER ARM IS IN SAIDSECOND